title: Molecular epidemiology and clinical characteristics of hepatitis B identified through the French mandatory notification system.
abstract: OBJECTIVE
  Strains responsible for acute hepatitis B infections (AHB) in France have not been characterized. This study was first designed to analyze the molecular epidemiology of AHB and second to describe the differences between AHB and chronic hepatitis B (CHB) exacerbations.
  
  
  METHODS
  This prospective study was based on the French mandatory notification system for AHB. 147 samples corresponding to declared cases were shipped to a central laboratory for classification as AHB or CHB according to the level of anti-HBc IgM and anti-HBc avidity.
  
  
  RESULTS
  Based on biological marker values and file examination, 75 cases (59%) were classified as AHB. Independently of the acute or chronic status, genotype A (57%), D (22%) and E (14%) were the most prevalent and no phylogenetic clustering was observed among HBV sequences (n=68). Precore or basal core-promoter variants were not particularly associated with disease severity but were more prevalent in CHB. No antiviral resistant strains or immune-escape HBsAg was observed. HBV viral loads in AHB or CHB were comparable but with opposite distributions. ALT levels reached 10 times the upper normal value in 94% of AHB but only in 24% of CHB.
  
  
  CONCLUSIONS
  After rigorous classification, no major difference at the genetic level was found between HBV strains isolated from AHB and CHB. Absence of potentially deleterious variant detection is reassuring. When based upon HBsAg and anti-HBc IgM determination, AHB notification may falsely include more than 40% CHB, leading to an important risk of bias in national surveillance programs of AHB.
authors.affiliation: Virology Laboratory, Hôpital Pitié-Salpêtrière, Assistance Publique (APHP), and Pierre et Marie Curie University, Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Thibault
authors.forename: Syria
authors.initials: S
authors.lastname: Laperche
authors.forename: Valérie
authors.initials: V
authors.lastname: Thiers
authors.forename: Sophie
authors.initials: S
authors.lastname: Sayon
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Letort
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Delarocque-Astagneau
authors.forename: Denise
authors.initials: D
authors.lastname: Antona
mesh_terms: D062665:Epidemiological Monitoring; D005602:France / Q000453:epidemiology; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology* / Q000821:virology*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D019221:Mandatory Reporting; D017720:Molecular Epidemiology / Q000379:methods; D015995:Prevalence; D011446:Prospective Studies